ClickHouse/dbms/src/Functions/array/range.cpp

112 lines
3.8 KiB
C++

#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <Functions/FunctionHelpers.h>
#include <DataTypes/DataTypeArray.h>
#include <Columns/ColumnArray.h>
#include <Columns/ColumnVector.h>
#include <numeric>
namespace DB
{
namespace ErrorCodes
{
extern const int ARGUMENT_OUT_OF_BOUND;
extern const int ILLEGAL_COLUMN;
extern const int ILLEGAL_TYPE_OF_ARGUMENT;
}
class FunctionRange : public IFunction
{
public:
static constexpr auto name = "range";
static FunctionPtr create(const Context &) { return std::make_shared<FunctionRange>(); }
private:
String getName() const override { return name; }
size_t getNumberOfArguments() const override { return 1; }
bool useDefaultImplementationForConstants() const override { return true; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
const DataTypePtr & arg = arguments.front();
if (!isUnsignedInteger(arg))
throw Exception{"Illegal type " + arg->getName() + " of argument of function " + getName(),
ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
return std::make_shared<DataTypeArray>(arg);
}
template <typename T>
bool executeInternal(Block & block, const IColumn * arg, const size_t result)
{
static constexpr size_t max_elements = 100'000'000;
if (const auto in = checkAndGetColumn<ColumnVector<T>>(arg))
{
const auto & in_data = in->getData();
const auto total_values = std::accumulate(std::begin(in_data), std::end(in_data), size_t{},
[this] (const size_t lhs, const size_t rhs)
{
const auto sum = lhs + rhs;
if (sum < lhs)
throw Exception{"A call to function " + getName() + " overflows, investigate the values of arguments you are passing",
ErrorCodes::ARGUMENT_OUT_OF_BOUND};
return sum;
});
if (total_values > max_elements)
throw Exception{"A call to function " + getName() + " would produce " + std::to_string(total_values) +
" array elements, which is greater than the allowed maximum of " + std::to_string(max_elements),
ErrorCodes::ARGUMENT_OUT_OF_BOUND};
auto data_col = ColumnVector<T>::create(total_values);
auto offsets_col = ColumnArray::ColumnOffsets::create(in->size());
auto & out_data = data_col->getData();
auto & out_offsets = offsets_col->getData();
IColumn::Offset offset{};
for (size_t row_idx = 0, rows = in->size(); row_idx < rows; ++row_idx)
{
for (size_t elem_idx = 0, elems = in_data[row_idx]; elem_idx < elems; ++elem_idx)
out_data[offset + elem_idx] = elem_idx;
offset += in_data[row_idx];
out_offsets[row_idx] = offset;
}
block.getByPosition(result).column = ColumnArray::create(std::move(data_col), std::move(offsets_col));
return true;
}
else
return false;
}
void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t) override
{
const auto col = block.getByPosition(arguments[0]).column.get();
if (!executeInternal<UInt8>(block, col, result) &&
!executeInternal<UInt16>(block, col, result) &&
!executeInternal<UInt32>(block, col, result) &&
!executeInternal<UInt64>(block, col, result))
{
throw Exception{"Illegal column " + col->getName() + " of argument of function " + getName(), ErrorCodes::ILLEGAL_COLUMN};
}
}
};
void registerFunctionRange(FunctionFactory & factory)
{
factory.registerFunction<FunctionRange>();
}
}